Letter regarding Li et al. entitled “Quantitative assessment of the association between CYP1A1 A4889G polymorphism and endometrial cancer risk”

Abstract

To the Editor, In a recent issue of Tumor Biology, Li and his workmates published an article [1] entitled “Quantitative assessment of the association between CYP1A1 A4889G polymorphism and endometrial cancer risk.” In this study, the authors performed a meta-analysis to a quantitative assessment of the association between CYP1A1 A4889G polymorphism and endometrial cancer risk. The authors found no association between CYP1A1 A4889G polymorphism and endometrial cancer risk. However, I have several opinions that I would like to communicate to the authors. Firstly, only two electronic databases (PubMed and China National Knowledge Infrastructure) for studies were systematically searched by the authors. The small number of required papers would be an important limitation of the review. I suggest at least three electronic databases should be systematically searched. Secondly, the authors had not focused specifically or in any details on the issue of the completeness of the search strategy report for databases. I suggest that the authors should provide me with the flow diagram of included studies for the metaanalysis. Search strategy report plays an important role in systematic reviews. If the PRISMA guidelines [2] had been followed, this would have been apparent to reviewers and readers and remedial action could have been taken. Thirdly, I suggest that the authors should evaluate the methodological quality of the selected studies, which could avoid the potential bias in the meta-analysis. Each included paper could be independently assessed by two reviewers using a standardized electronic form of predefined criteria. And the authors could describe how to assess the quality of all studies in the meta-analysis, and there were detailed scores for each trial. I agree on the following conclusions of the authors: evidence for currently available data suggests that CYP1A1 A488 9G polymorphism is not associated with endometrial cancer risk. Moreover, more carefully and scientifically designed studies with large samples are still needed. I believe that these remarks will contribute to further, more accurate elaboration and substantiation of the original results presented by Li et al. [1].